Hyperbaric oxygen in epidural fibrosis: is there a potential for treatment?

AIM: To investigate the effects of hyperbaric oxygen treatment on epidural fibrosis formation in an experimental laminectomy model. MATERIAL AND METHODS: Twenty-four Wistar rats underwent L5-L6 total laminectomy and divided into three groups. Animals in the control group received no further treatment while animals in short and long term groups received 2,5 ATM ABS of hyperbaric oxygen for 3 and 7 days, respectively. The amount of epidural fibrosis was analyzed histologically at the end of 42 days of follow up. RESULTS: The ratio of severe fibrosis was 57% in the control, 29% in the short HBOT, and 14% in the long HBOT groups. Although there was a clear trend towards having less fibrosis in the HBOT groups, the difference did not reach to the level of statistical significance (p=0.242), probably due to small number of animals used in this preliminary study. CONCLUSION: Our findings suggest that hyperbaric oxygen treatment may have favorable effects on epidural fibrosis. Further studies with larger cohorts are required to prove our results.

Neuroprotective effects of gabapentin on spinal cord ischemia-reperfusion injury in rabbits.

OBJECT: Extensive research has been focused on neuroprotection after spinal cord trauma to alleviate the effects of secondary injury. This study aims to investigate the neuroprotective effects of gabapentin in an experimental spinal cord ischemia reperfusion injury. METHODS: Thirty-two adult male New Zealand white rabbits received spinal cord ischemic injury using the aortic occlusion model. Animals were divided into 4 groups (sham, control, low-dose, and high-dose treatment groups; 8 rabbits in each group). High (200 mg/kg) and low (30 mg/kg) doses of gabapentin were administered to the animals in the treatment groups after spinal cord ischemic injury. Neurological status of the animals, ultrastructural findings in injured tissue samples, and levels of tissue injury markers in these 2 groups were compared with findings in the animals that did not receive the ischemic procedure (sham-operated group) and those that received normal saline after administration of ischemia. RESULTS: Regarding levels of tissue injury marker levels after ischemic injury, animals in the gabapentin-treated groups demonstrated better results than animals in the other groups. The ultrastructural findings and caspase-3 activity were similar. The treatment groups demonstrated better results than the other groups. CONCLUSIONS: Gabapentin demonstrated significant neuroprotection after early phases of ischemic injury. Further studies with different experimental settings including neurological outcome are required to achieve conclusive results.

Neuroprotective effects of gabapentin in experimental spinal cord injury.

BACKGROUND: Extensive research has focused on neuroprotection after spinal cord trauma to alleviate the effects of secondary injury. This study aims to investigate the neuroprotective effects of gabapentin in experimental spinal cord injury. METHODS: Thirty-six adult, male Wistar rats received spinal cord injury using the clip compression method. Animals were divided into five groups. High (200 mg/kg) and low doses (30 mg/kg) of gabapentin were administered to the animals in the treatment groups after spinal cord trauma and ultrastructural findings and lipid peroxidation levels of these two groups were compared with the animals that received only laminectomy, only trauma, and trauma and 30 mg/kg methylprednisolone. RESULTS: Regarding tissue lipid peroxidation levels after trauma, animals in gabapentin groups demonstrated better results than the trauma group. However, these results were no better than the methylprednisolone group. The results regarding the ultrastructural findings were similar. Treatment groups demonstrated better ultrastructural findings than the trauma group. In addition, the results of the high dose gabapentin group were significantly better than the low dose gabapentin group. CONCLUSIONS: Gabapentin demonstrated similar neuroprotective effects as methylprednisolone in early phase of spinal cord injury. Further studies with different experimental settings including neurological outcome are required to achieve conclusive results.

Role of antifibrotic cytokine interferon-gamma in the prevention of postlaminectomy peridural fibrosis in rats.

OBJECTIVE: Extensive peridural fibrosis after spinal surgery may be the underlying cause of failed-back syndrome in some cases. There is increasing evidence that generation of specific cytokine patterns by immune and structural cells and interactions among these cells mediate many of the key events involved in fibrogenesis. Interferon-gamma (IFN-gamma) has several potential antifibrotic actions, including inhibition of fibroblast proliferation and collagen deposition, promotion of fibroblast apoptosis, and inhibition of production and action of the fibrogenic cytokine, transforming growth factor-beta. We conducted a study to determine the effectiveness of IFN-gamma in preventing postlaminectomy peridural fibrosis in rats. To the best of our knowledge, this is the first study testing immunotherapy in peridural fibrosis. Type 2 cytokine hypothesis of fibrogenesis is emphasized. METHODS: Laminectomies were performed in 30 rats. We administered 2000 U/d IFN-gamma, 20,000 U/d IFN-gamma, or 0.2 ml/d saline to the laminectomy site through a silicone catheter for 3 days in blinded fashion. The amount of scar tissue, fibroblast density, inflammatory cell density, arachnoidal involvement, and bone regeneration were analyzed histologically. RESULTS: Histopathological examination showed a significantly reduced amount of scar tissue and fibroblast density in the low-dose IFN-gamma group compared with the control and high-dose IFN-gamma groups. A significant increase was detected in inflammatory cell density in the high-dose IFN-gamma group compared with the control and low-dose IFN-gamma groups. CONCLUSION: Cytokines play a critical role in wound healing, tissue repair, and fibrogenesis. This study suggests that topical application of low-dose IFN-gamma is an effective and safe method of preventing peridural fibrosis, but further studies with different doses, durations, and intervals are required to achieve better results.